A population-based case-control study of osteosarcoma cases is proposed among residents of New York State who were diagnosed between 1978 and 1987, at 24 years of age or younger. The primary focus of this research is to test whether there is a positive association between exposure to fluoride in a non-occupational setting and the onset of childhood osteosarcoma. In addition, this study will also investigate other potential risk factors such as growth and development, previous bone trauma, and prenatal exposure to chemicals and radiation. Cases will be identified from the New York State Cancer Registry. An equal number of controls will be chosen from live birth records. The controls will be frequency matched to the cases regarding sex, year of and age at diagnosis using an innovative method. Each person will be traced from the date of diagnosis to the present using Motor Vehicle records, telephone directories and other methods. The primary source of exposure data will be telephone interviews with the subjects and/or their parents. Medical, dental and school health records also will be abstracted for a random 50% sub-sample. The data obtained from these records will be used to validate the interview information. Logistic regression analysis and other statistical techniques will be used to assess the effect of risk factors controlling for confounding variables such as sociodemographic status. Due to the common practice of fluoridating drinking water and the protective effect of fluoride against dental caries, it is important to determine whether fluoride intake could be an etiologic factor for osteosarcoma. This study also satisfies the requirements of the program announcement for small grants by investigating an emergent issue in cancer epidemiology, by planning a complex epidemiologic investigation, and by developing a new methodologic procedure for frequency matching.